Bulletin of the American Physical Society
APS April Meeting 2022
Volume 67, Number 6
Saturday–Tuesday, April 9–12, 2022; New York
Session D10: Inflation, Dark Energy, and BaryogenesisRecordings Available

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Sponsoring Units: DPF Chair: Matthew Szydagis, U Albany SUNY Room: Salon 3 
Saturday, April 9, 2022 1:30PM  1:42PM 
D10.00001: Scalar perturbations in massive gravity in the presence of matter Ekapob Kulchoakrungsun, Ananya Mukherjee, Nishant Agarwal, Anthony Pullen The de RhamGabadadzeTolley (dRGT) theory provides a consistent massive extension of general relativity, but stable selfaccelerating solutions within it have been elusive. The quasidilaton extension of the dRGT theory allows for such solutions by introducing an additional scalar field with a global rescaling symmetry. In this talk, I will discuss scalar perturbations in the extended quasidilaton theory in the presence of matter. I will first briefly introduce the theory and the selfaccelerating background evolution where the quasidilaton (in the presence of a massive graviton) can act as an effective cosmological constant. I will next discuss the general calculation of scalar perturbations without restricting to any choice of gauge. I will then choose a particular form for matter where a unitary gauge for matter fields is most convenient to work in and present the kinetic matrix calculation for all propagating scalar degrees of freedom. I will show that the conditions for positive eigenvalues can be satisfied, and the theory can thus remain ghostfree on the selfaccelerating solution in the presence of matter. Lastly, I will briefly discuss the linear growth of structure in this theory, that the next talk will describe in more detail. 
Saturday, April 9, 2022 1:42PM  1:54PM 
D10.00002: Cosmological constraints on massive gravity Ananya Mukherjee, Ekapob Kulchoakrungsun, Nishant Agarwal, Anthony Pullen As discussed in the previous talk, a promising approach to explain the current accelerated expansion of the Universe is to extend general relativity to include a nonzero graviton mass. The resulting modification is expected to lead to different background expansion and growth of structure compared to the standard cosmological constant with cold dark matter model. In this talk, I will present results on the growth of matter perturbations in a quasidilaton extension of the de RhamGabadadzeTolley (dRGT) theory of massive gravity, that allows for a stable cosmology. Starting in conformal Newtonian gauge, where scalar perturbations coincide with gaugeinvariant ones, I will first obtain coupled differential equations in all propagating degrees of freedom. I will next discuss two subhorizon approximations that allow us to find a single equation describing the growth of matter perturbations and show how the resulting growth of structure compares to the standard cosmological model. Lastly, I will discuss the constraints on various model parameters, including the mass of the graviton, from a MarkovChain MonteCarlo analysis that compares the background evolution to supernovae data and the growth of perturbations to galaxy clustering data. 
Saturday, April 9, 2022 1:54PM  2:06PM 
D10.00003: BICEP/Keck Constraints on Attractor Models of Inflation and Reheating Sarunas Verner Recent BICEP/Keck data on the cosmic microwave background, in combination with previous WMAP and Planck data, impose strong new constraints on the tilt in the scalar perturbation spectrum, n_{s}, as well as the tensortoscalar ratio, r. These constrain the number of efolds of inflation, N*, the magnitude of the inflaton coupling to matter, y, and the reheating temperature, T_{RH.} We evaluate the number of efolds N* numerically in attractor models of inflation (TModels and E Models). We show that the 68% C.L. region of (n_{s}, r) plane favors large values of N*, y, and T_{RH}, and these parameters are constrained by the production of gravitinos and supersymmetric dark matter. We also show the minimum reheating temperature that is compatible with Big Bang Nucleosynthesis (BBN). Finally, we discuss the impacts of the BICEP/Keck and other constraints on E and TModels of inflation. 
Saturday, April 9, 2022 2:06PM  2:18PM 
D10.00004: Searching for Chameleon Dark Energy with Mechanical Systems Joey Betz, Jack Manley, Ewan Wright, Daniel Grin, Swati Singh We consider using optically levitated microspheres and torsion balances as screened scalar field detectors. We present a novel derivation for the classical chameleon force between two spherical bodies which remains valid at smaller separation distances and stronger chameleon couplings than previous work. Using this and experimental sensitivities achieved by the current generation of experiments, we show predicted constraints on chameleons as dark energy. We include analytic expressions for the parameter space that can be probed by future experiments in terms of experimental parameters. We also indicate regions of theoretically wellmotivated chameleon parameter space which should be the aim for future experiments. 
Saturday, April 9, 2022 2:18PM  2:30PM 
D10.00005: Signature of heavy physics in stochastic gravitationalwave background Arushi Ravindra Bodas Sudden onset of classical oscillations of a heavy field (mass greater than the inflationary Hubble scale) leaves a characteristic scaleinvariancebreaking oscillatory feature in the power spectrum of primordial fluctuations. The presence of these features provides a unique opportunity to detect the dynamics of heavy fields during inflation. While such features are constrained to be small in curvature perturbations, we show that it may not be the case for isocurvature perturbations. I will demonstrate the possibility of observing large primordial features in the stochastic gravitationalwave (GW) background originating from a firstorder phase transition in a hidden sector. I will show that the signal can be observably large in the GW map while being completely hidden in the standard curvature perturbations such as those of the Cosmic Microwave Background. 
Saturday, April 9, 2022 2:30PM  2:42PM 
D10.00006: Dark energy of the photon space, inflation of the charged black holes and universe evolution JaeKwang Hwang Spacetime evolution of our universe is explained by using the 3dimensional quantized space model (TQSM) based on the 4dimensional (4D) Euclidean space. The energy (E = cΔtΔV), charges and energy density (q = ρ = cΔt) and absolute time (ct) are newly defined based on the 4D Euclidean space. The photon flat space with the constant energy density of ρ = cΔt_{q} is proposed as the dark energy (DE). The dark energy is separated into the ν DE and photon DE which create the new photon spaces with the constant energy density of ρ = cΔt_{q}. The v DE is from the ν pair production by the CPT symmetry and the photon DE is from the photon space pair production by the T symmetry. The vacuum energy crisis and Hubble’s constant puzzle are explained by the photon space with the ν DE and photon DE. The big bang and inflation of the primary black hole is connected to the accelerated space expansion and big collapse of the photon space through the universe evolution. The big bang from the nothing is the pair production of the matter universe with the positive energy and the partner antimatter universe with the negative energy from the CPT symmetry. Our universe is the matter universe with the negative charges of electric charge (EC), lepton charge (LC) and color charge (CC). 
Saturday, April 9, 2022 2:42PM  2:54PM 
D10.00007: Testing AffleckDine Baryogenesis with Gravitational Waves Lauren M Pearce The source of the observed cosmological baryon excess is unknown, but a popular proposal is AffleckDine baryogenesis. In this model, the asymmetry is produced during the evolution of a scalar condensate, which fragments into nontopological solitons (Qballs). If these Qballs are sufficiently longlived, then they may dominate the energy density of the universe before decaying, releasing their baryon charge into the plasma. The decays of charged quanta into Standard Model fermions can occur only at the surface of the Qball, and so the decay rate increases as the Qball shrinks. From a cosmological perspective, Qball decay is effectively instantaneous, similar to black hole decay, and so the universe undergoes a rapid transition from matter to radiation domination. The Qball overdensities become sound waves in the plasma, which source gravitational waves, and a particular frequency is resonantly enhanced (as with primordial black holes, the socalled "poltergeist mechanism"). For wellmotivated regions of parameter space, this peak is in the detectable range of the Einstein telescope and/or DECIGO, providing a new opportunity to test AffleckDine baryogenesis. 
Saturday, April 9, 2022 2:54PM  3:06PM 
D10.00008: Decaying Dark Matter at IceCube and its Signature in HighEnergy GammaRay Experiments Barbara Skrzypek, Carlos A Arguelles, Marco Chianese Observations of highenergy astrophysical neutrinos in IceCube have opened the door to multimessenger astronomy, by way of which questions in particle physics could be explored through a combination of IceCube data and optical experiments such as FermiLAT. However, the origin of these astrophysical neutrinos is still largely unknown. Among the tensions that still need to be addressed, for example, is the excess of neutrinos observed in the energy range of 40200 TeV, a contribution that could come from heavy dark matter decay. The dark matter decay hypothesis can be tested through comparisons with gammaray data, because a coincident gammaray flux is expected to accompany the neutrino flux that IceCube observes. However, gammarays become heavily suppressed for sources dominating in particular energy ranges. In the case of the Galactic center, the $\gamma$sky is partially opaque in the (0.110) PeV range. This is due to properties of the traversed medium, which consists of extragalactic background light (EBL), the cosmic microwave background (CMB), and the intergalactic magnetic field. These significantly alter the initial spectrum through intermediate processes such as absorption and InverseCompton scattering, giving rise to anisotropy and energy features in the final spectrum that reaches telescopes on Earth. The existence of competing photon background models, moreover, complicates estimates of dark matter constraints. In this presentation, we address these questions by studying the impact that these different models have on indirect measurements of heavy dark matter decay. I present my predictions for galactic, inverseCompton, and extragalactic gammaray spectra undergoing attenuation by different backgrounds. 
Saturday, April 9, 2022 3:06PM  3:18PM 
D10.00009: Lambda as a Measure of the Rate of Recursion of Geometric Algebras Dennis W Marks Geometric algebras over the real numbers are isomorphic to certain matrices–dyreal, real, complex, quaternionic, or dyquaternionic–depending only on the metric signature s, the number of spatial dimensions minus the number of temporal dimensions. The rank of each kind of matrix depends only on the total number n of dimensions, spatial plus temporal. Geometric algebras over the reals are periodic in s, but recursive in n. The recursion is generated from the anticommuting basis vectors of either the Euclidean plane or the Minkowskian plane. Certain direct products of the geometric elements of these two planes form the basis vectors of 4dimensional Minkowskian spacetime if the resulting basis vectors do not curl up on themselves. If they do, the resulting geometric algebra generates the Standard Model of physics, with 4 real dimensions of spacetime and 12 real curledup dimensions (rather than the 6 complex curledup dimensions of MTheory). After eight dimensions, the pattern of geometric algebras repeats itself, resulting in a recursively generated, exponentially expanding spacetime lattice with the Standard Model at each node of the lattice. The cosmological constant is set by the rate of recursion, a different process from the curlingup process that sets the Planck scale. 
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